JPH0429308B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a resolver in which the stator and rotor have different numbers of teeth, in which the stator is provided with primary and secondary windings, and one of the windings is excited from an excitation electrode. This invention relates to a resolver that detects the rotational position of a rotor from the other winding.

In a conventional vernier resolver, the stator is a cylindrical laminated core with N _s teeth cut at equal pitches on the inside, and the rotator is a circular laminated core with N _r teeth cut on the outside. The teeth are cut into equal parts with a pitch.

Then, choose the number of stator teeth N _s and the number of rotor teeth N _r as N _s = N _r ±N _p , where N _p is a small integer and the number of teeth N _s
Its characteristic is that it is N _{s r} because it is a fraction of N _r .

However, with this vernier resolver, there is a limit to the ability to improve the waveform by adjusting the tooth profile, skew shape, etc., and the winding tends to become complicated because the pitch and number of turns must be adjusted.

Furthermore, in the conventional inductor resolver, where m ₁ is the number of phases of the primary winding, N _s = 2m ₁ N _r and N _s /N _r =
2m ₁ without using vernier.

Therefore, unlike the vernier resolver mentioned earlier, inductor resolvers do not have the freedom to adjust the windings, making it difficult to adjust the waveform. The problem is that it becomes complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vernier inductor resolver which overcomes the drawbacks of prior art devices.

The vernier type inductor resolver of the present invention can easily improve the waveform because both the rotor teeth and the secondary winding can be adjusted, and the primary winding can be multiphased compared to conventional types. It's easy.

That is, the basic idea of the present invention is that between the number of stator teeth _Ns , the number of rotor teeth _Nr , the number of phases of the primary winding _m1 , and an integer _Np of 1 or more, _Ns = _2m1 ( This resolver should be called a vernier type inductor resolver, which has the following relationship: N _r ±N _p ).

Incidentally, for a conventional vernier resolver, N _s =N _r ±N _p , and for a conventional inductor resolver, N _s = 2m ₁ Nr.

The principle of the present invention will now be described.

In a vernier resolver, the air gap permeance (permeance permeability) when the integer N _p =2 is expressed as shown in FIG.

At points A and A', the teeth of the stator and rotor match,
Since there is a discrepancy at points B and B', the permeance at points A and A' is maximum, and at points B and B' it is minimum. This is represented by a rotor 100 having virtual salient poles.
Note that 200 is a stator. Here, in order to create the vernier type inductor resolver of the present invention in which the number of phases of the primary winding m ₁ = 1, the number of stator teeth N _s is doubled, and adjacent stator teeth have opposite polarities. By winding the wires and connecting them in series, a primary single-phase coil is formed.

Figure 2 shows the air gap permeance λ _F for the positive polarity magnetomotive force of this primary coil and the air gap permeance λ _R for the reverse polarity magnetomotive force of the virtual salient pole rotor 10.
It is an explanatory diagram expressed in 0,100'. At the point where the permeance λ _F for the positive polarity magnetomotive force is maximum, the empty permeance λ _R for the reverse polarity magnetomotive force is the minimum, so the relationship is completely opposite.

Assuming that the primary coil is excited with alternating current and the secondary coil is wound around the stator with four distributed poles, the distribution of air gap magnetic flux φ is (λ _F −λ _R )F ₁ = φ By the way, λ _F = λ ₀ +λcos2θ λ _R =λ ₀ +λcos2θ, so φ=F ₁・2λcos2θ Therefore, the induced voltage e ₂ of the secondary coil is θ=
+η as e ₂ ∝∫ ⁺ 〓 _- 〓φn ₂ cos2ηdη ∝∫ ⁺ 〓 _- 〓cos2(+η)cos2ηdη ∝cos2 where is the electrical angle of the secondary coil axis measured from the rotor virtual salient pole axis AA′, and θ is variable, η is the electrical angle (variable) measured from the secondary coil axis CC′ at η = θ−, F ₁ is the supermagnetic force of the primary coil, λ ₀ is the constant component of the air gap permeance, and λ is the variable component of the air gap permeance. The amplitude is .

Next, the basic magnetic structure of the present invention will be described.

The stator of the present invention has a cylindrical laminated core, and N _s teeth are formed at equal pitches on the inside of the core.
The rotor has a similar laminated core with N _r teeth cut at equal pitches on the outside, and is inserted into the stator through gaps.

If N _s =N _r ±N _p , then if N _p =1, the opposing teeth of the stator and rotor will be aligned at only one location. If N _p =2, the stator and rotor teeth are aligned at two locations 180° apart, and when N _p =3, the stator and rotor teeth are aligned at three locations 120° apart.
Therefore, for N _p teeth, N _p teeth are perfectly aligned at locations separated by 360°/N _p .

Permeance is maximum where the stator and rotor teeth are aligned, and minimum where they are completely misaligned.

Therefore, it can be said that the air gap permeance has N _p virtual salient poles.

When the rotor rotates 360°/N _r (1 pitch angle),
The magnetic path returns to its original state, but the air gap permeance wave,
That is, the virtual salient pole rotates by 360°/N _p (one salient pole pitch angle). Therefore, the permeance wave for the rotor is
It can be seen that the speed is increased by a factor of N _r /N _p .

In contrast to 360°/N _s, 360°/N _r corresponds to a pernier scale, and the scales coincide every 360°/(N _s to N _r ).
For this reason, it is called a vernier resolver.

Here, try doubling the stator tooth _Ns . Assume that there have been teeth #1, #2, ..., _#Ns , and insert #1', #2', ..., _#Ns ' between them as follows.

#1, #1', #2, #2', ..., #(N _s -1),
#(N _s −1)′, #N _s , #N _s ′, #10 #1 to #N _s
For the air gap permeance wave λ _p seen from #1′~
The air gap permeance wave λ _p ′ seen from #N _s ′ is 360°/
It is located at a position advanced by (2N _p ). An example of N _p =2 is shown in FIG. This means that where the teeth #1 to _#Ns are aligned with the rotor (Figure 4), the teeth #1' to _#Ns ' are misaligned, and where the teeth #1 to _#Ns are misaligned ( In Figure 5), #1' to #N _s ' match, which is intuitively understandable since the relationship is reversed.

Here, it is assumed that #1 to _#Ns are wound to the right and #1' to _#Ns ' are wound to the left, and an excitation coil in which these are connected in series is excited with alternating current. An alternating magnetic field with a 2N _s pole is generated in the air gap, but the magnitude of the generated magnetic flux is modulated by the permeance wave.

In the example of N _p = 2, if a 4-pole multiphase distributed winding is applied to the stator, a magnetic flux of λ _p −λ _p ′ = λcos2θ−(−cos2θ) = 2λcos2θ is generated in this air gap, so A primary single phase/secondary multiphase resolver can be configured.

Next, the number of stator teeth is further doubled to 4N _s , and as shown in FIG. 6, k ₁ and k ₁ ' form one phase coil, and k ₂ and k ₂ ' form another phase coil. In this way, k ₁ ,
For the permeance wave λ _p1 for the k ₁ ′ phase, k ₂ ,
The permeance wave λ _p2 for the k ₂ ′ phase advances by 90° in electrical angle.

In this way, generally by increasing the number of stator teeth to 2m ₁ N _s , it is possible to form k ₁ k ₁ ′, k ₂ k ₂ ′, . . . , k _n1 k _n1 ′ phases.

The selection of the number of teeth and the balance of the magnetic path are as follows.

Considering a resolver with primary m ₁ phase and secondary m ₂ phase,
N _s = 2m ₁ (N _r ±N _p ), and the number of stator teeth N _s is N _p ×2m ₂
It must be divisible by .

If n is an integer, n=N _s / (N _p × 2m ₂ ) = (m ₁ / m ₂ ) (N _r ±N _p
)/N _p = (m ₁ /m ₂ ) (N _r /N _p ±1) Therefore, (N _r /N _p ±1)/m ₂ should be an integer.

If the integer N _p =1 for the primary two-phase and secondary two-phase resolvers, (N _r ±1) 12 = n, that is, N _r ±1 = 2n. Therefore, the number of rotor teeth N _r becomes an odd number.

If the number of secondary phases m ₂ =1 and the integer N _p =1, the number of rotor teeth N _r can be freely selected.

If the number of rotor teeth N _r = 4 If the number of primary phases m ₁ = 2, then the number of stator teeth N _s is N _s = 2 × 2 (4 ± 1) = 20/12 If the number of primary phases m ₁ 2, then an integer Even if N _p =1, the magnetic path is balanced. When the integer N _p is increased, the number q of grooves for each pole and each phase of the secondary winding is reduced, so the balance of the magnetic path is good, but the degree of freedom of the winding is reduced. The structure that increases precision lies in choosing an integer N _p appropriately.

An embodiment of the present invention will now be described.

An 8-pole primary 2-phase, secondary 1-phase resolver is used as an example of a pole sensor for a brushless DC servo motor.

Number of rotor teeth N _r = 4 Integer N _p = 1 Number of stator teeth N _s = 2 × 2 (4 ± 1) = 20/12 An explanatory diagram of this number of stator teeth N _s = 12 is shown in Fig. 7 .

As the primary winding, The a phase is (1, -1', 2, -2', 3, -3') year, The b phase is (-1, -1', -2, -2', -3, -3') Wind each.

As for the secondary winding, a single-phase two-pole winding is distributed distributed using the 12 slots.

For example, (-3', -1), (-2', -2) n ₁ turn (-3', 1'), (-3, 2) n ₂ turns (-3, -1') n ₃ turns And it is sufficient.

FIG. 8 is an explanatory diagram of the number of stator teeth N _s =20.

As the primary winding, the a phase is (1, -1', 2, -2', 3, -3', 4, -4
′,
5, -5'), and the b phase is (1, -1', 2, -2', 3, -3'4, -
4', 5, -5') respectively.

As for the secondary winding, the 20 slots are freely used to distribute and wind the single-phase, two-pole winding.

In both the structures shown in FIGS. 7 and 8, it is easy to convert the secondary into two phases. All you have to do is wind the windings orthogonally.

Furthermore, let's consider a 72-pole primary 1-phase and secondary 2-phase resolver that detects the speed of an AC servo and the mechanical angle of an NC machine tool.

Number of rotor teeth N _r = 36 Integer N _p = 2 Number of stator teeth N _s = 2 × 1 (36 ± 2) = 76/68 Or Number of rotor teeth N _r = 36 Integer N _p = 4 Number of stator teeth N _s = 2 × 1 (36 ± 4) = 80/64 Various types are possible, but the number of stator teeth N _s = 64
If selected, N _s / (N _p ×2 m ₂ ) = 64 / (4 × 2 × 2) = 4, which corresponds to the number of grooves q for each pole and each phase.

As described above, many structures are possible.

Thus, according to the present invention, the following effects are recognized.

○A A major feature is that the secondary winding can be a 2N _p -pole multiphase distributed winding. Therefore, there is a high degree of freedom in the winding for reducing harmonic components, and a highly accurate resolver can therefore be obtained.

○B Since the secondary winding can also be multiphased, processing becomes easier when converting this signal into pulses.

○C The range of applications of this type of resolver covers all speed and position control of servo actuators, including N/C machine tools and robots, and this highly reliable, highly accurate, and low-cost structure is being explored. However, the present invention is a resolver with great future potential because it has a simple structure, high accuracy, and has many degrees of freedom in that it can obtain multiphase signals.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of air gap permeance representing the principle of the present invention, FIGS. 3 to 6 are explanatory diagrams of the operation of the present invention, and FIG. 7 is a sectional view of an embodiment of the present invention. FIG. 8 is a sectional view of another embodiment of the present invention. 100...Rotor, 200...Stator.

Claims (1)

[Claims] 1. The stator is a cylindrical soft magnetic material with N _s teeth formed at equal pitches on the inside, and the rotor is a circular soft magnetic material with N _r teeth formed on the outside. In addition, when m ₁ is the number of phases of the primary winding and N _p is an integer greater than or equal to 1, there is a relationship of N _s = 2m ₁ (N _r ±N _p ), and the primary winding is Each phase is formed by connecting in series a coil wound with alternating polarity every (m ₁ -1) stator teeth, and the secondary winding is a 2N _p- pole distributed winding on the stator. By forming m ₂ phases and inserting the rotor into the stator through an equal gap, a 2N _r -pole resolver with m ₁ phase on the primary side and m ₂ phases on the secondary side is constructed. Features a vernier type inductor resolver.